The examination of the human face can provide dynamic, varied, and plentiful information. Facial data conveys the identity of the person under observation and can later be used to confirm that identity. Facial information further conveys a mood and a mental state or mental states of a person. The capture and analysis of facial information data of a person is undertaken for a wide variety of purposes and practical applications, including determination of a range of emotions and mental states, facial recognition, motion capture, eye tracking, lie detection, computer animation, and other applications. The analysis of facial information data can also be used for the tracking of facial motions, gestures, gaze directions, head poses, expressions, and so on. The applications for the analysis of facial information are both varied and wide ranging, and include product and service market analysis, biometric and other identification, law enforcement applications, social networking connectivity, and healthcare processes, among many others. The analysis is often based on viewing a face, facial expressions, facial features, movements of facial muscles, etc. The results of the analysis can be used to determine emotional and mental states, identity, veracity, and so on, of the person or persons being analyzed. Facial analysis is often used for tracking purposes. The tracking component is often employed to locate a person or persons, and can be used to predict future movement and location of the person or persons. Such geographical tracking has many practical applications including sporting event coverage, law enforcement applications, disease propagation detection, computer gaming events, social networking connectivity, and so on.
Humans are particularly good at processing facial information data for a variety of purposes. Perhaps foremost among the varied purposes is social interaction. The social interaction can be among strangers, friends, family members, and so on. The facial processing is critical to personal safety and even survival in some cases, and is used for such basic human activities as social interactions including cooperation, locating a mate, etc. The facial processing is used to rapidly identify whether a stranger appears friendly and approachable or appears dangerous and should be avoided. Similarly, the processing can be used to quickly determine a friend's mood, the mental state of a family member, and so on. The processing of facial information data is used to draw attention to important objects or events in one's environment, such as potential sources of physical danger requiring an immediate and appropriate response.
Analysis of facial information data becomes difficult for people and for processors when the desired facial information data is captured along with other undesirable data. Imagine for example, that one friend is looking for another friend in a crowd at a sporting event, music concert, political convention, or other large group activity. The flood of spurious data that is captured simultaneously with the facial information data of the sought-after friend confounds the facial information data. This saturation of the facial information data complicates the search for the friend in the crowd. The spurious data must be separated from the facial information data in order to obtain the desired outcome, which in this case is the detection of one's friend in the crowd. The detection of one's friend is further complicated if the friend is moving along with the rest of the crowd. In this scenario, the friend may not be visible at all times, as he or she is moving in and out of sight among the crowd.